El Dorado, Kan. – The Butler County Health Department is encouraging all individuals to get their flu vaccine. It is not too late to still be covered for this year’s strain of flu. Everyone 6 months and older should get an annual flu vaccine. It takes about 2 weeks after vaccination for your body to develop an immune response, which will last for an entire year. A vaccination is required every year because flu viruses constantly change, so flu vaccines are updated every season to protect against the current circulating viruses. Yearly vaccination is recommended even for those who received the vaccine during the previous flu season. The health department still has a limited number of doses of influenza vaccine. The cost for flu vaccination is currently $23.00 at the health department.